Moving apps to an SD card on the Samsung Galaxy 5

i have a Samsung Galaxy S5. I have just put in an SD card for extra space. I have been able to move some apps and files over to the SD card, but there are many apps that I'm not able to do that as the "move to Sd" is greyed out and not selectable. Any ideas on how I can get them moved over?

If the move to SD button is not available, there is no way to move the app to the SD card. The reason this function is not available may be that it need to run some service, handle background syncing or access an account. It may not be able to perform those functions consistently if located on the SD card. It is also the developers choice whether to allow their app to be moved to the SD card whether its functionality requires it to be stored on the phone or not.